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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN""http://www.w3.org/TR/REC-html40/loose.dtd"><!--NewPage--><HTML><HEAD><!-- Generated by javadoc on Wed Jan 15 11:28:22 CET 2003 --><TITLE>JQueue</TITLE><META NAME="keywords" CONTENT="javatools.util.JQueue,JQueue class"><LINK REL ="stylesheet" TYPE="text/css" HREF="../../stylesheet.css" TITLE="Style"></HEAD><SCRIPT>function asd(){parent.document.title="JQueue";}</SCRIPT><BODY BGCOLOR="white" onload="asd();"><!-- ========== START OF NAVBAR ========== --><A NAME="navbar_top"><!-- --></A><TABLE BORDER="0" WIDTH="100%" CELLPADDING="1" CELLSPACING="0"><TR><TD COLSPAN=3 BGCOLOR="#EEEEFF" CLASS="NavBarCell1"><A NAME="navbar_top_firstrow"><!-- --></A><TABLE BORDER="0" CELLPADDING="0" CELLSPACING="3"> <TR ALIGN="center" VALIGN="top"> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="../../overview-summary.html"><FONT CLASS="NavBarFont1"><B>Overview</B></FONT></A> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="package-summary.html"><FONT CLASS="NavBarFont1"><B>Package</B></FONT></A> </TD> <TD BGCOLOR="#FFFFFF" CLASS="NavBarCell1Rev"> <FONT CLASS="NavBarFont1Rev"><B>Class</B></FONT> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="package-tree.html"><FONT CLASS="NavBarFont1"><B>Tree</B></FONT></A> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="../../deprecated-list.html"><FONT CLASS="NavBarFont1"><B>Deprecated</B></FONT></A> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="../../index-all.html"><FONT CLASS="NavBarFont1"><B>Index</B></FONT></A> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="../../help-doc.html"><FONT CLASS="NavBarFont1"><B>Help</B></FONT></A> </TD> </TR></TABLE></TD><TD ALIGN="right" VALIGN="top" ROWSPAN=3><EM></EM></TD></TR><TR><TD BGCOLOR="white" CLASS="NavBarCell2"><FONT SIZE="-2"> <A HREF="../../javatools/util/IteratorToEnumeration.html"><B>PREV CLASS</B></A> <A HREF="../../javatools/util/JQueue.QueueKey.html"><B>NEXT CLASS</B></A></FONT></TD><TD BGCOLOR="white" CLASS="NavBarCell2"><FONT SIZE="-2"> <A HREF="../../index.html" TARGET="_top"><B>FRAMES</B></A> <A HREF="JQueue.html" TARGET="_top"><B>NO FRAMES</B></A> <SCRIPT> <!-- if(window==top) { document.writeln('<A HREF="../../allclasses-noframe.html" TARGET=""><B>All Classes</B></A>'); } //--></SCRIPT><NOSCRIPT><A HREF="../../allclasses-noframe.html" TARGET=""><B>All Classes</B></A></NOSCRIPT></FONT></TD></TR><TR><TD VALIGN="top" CLASS="NavBarCell3"><FONT SIZE="-2"> SUMMARY: <A HREF="#nested_class_summary">NESTED</A> | FIELD | <A HREF="#constructor_summary">CONSTR</A> | <A HREF="#method_summary">METHOD</A></FONT></TD><TD VALIGN="top" CLASS="NavBarCell3"><FONT SIZE="-2">DETAIL: FIELD | <A HREF="#constructor_detail">CONSTR</A> | <A HREF="#method_detail">METHOD</A></FONT></TD></TR></TABLE><!-- =========== END OF NAVBAR =========== --><HR><!-- ======== START OF CLASS DATA ======== --><H2><FONT SIZE="-1">javatools.util</FONT><BR>Class JQueue</H2><PRE>java.lang.Object | +--<B>javatools.util.JQueue</B></PRE><HR><DL><DT>public class <B>JQueue</B><DT>extends java.lang.Object</DL><P>Implements a regular queue. The only unusual thing is you can delete things from the middle of the queue efficiently by supplying the QueueKey which is returned by put(). In terms of implementation we use a Dictionary Hashtable instead of a perhaps more traditional vector with round-robin pointers. The benefit here is efficient implementation of the remove functionality. It also happens to be a really easy way to implement queues in general. The way it works is that the dictionary is used as a sparse array. The upper and lower bounds of the sparse array keeping growing up and up towards infinity. This is ok because the key is a long and will take several million years of running before any problems arise.<P><P><HR><P><!-- ======== NESTED CLASS SUMMARY ======== --><A NAME="nested_class_summary"><!-- --></A><TABLE BORDER="1" CELLPADDING="3" CELLSPACING="0" WIDTH="100%"><TR BGCOLOR="#CCCCFF" CLASS="TableHeadingColor"><TD COLSPAN=2><FONT SIZE="+2"><B>Nested Class Summary</B></FONT></TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> class</CODE></FONT></TD><TD><CODE><B><A HREF="../../javatools/util/JQueue.QueueKey.html">JQueue.QueueKey</A></B></CODE><BR> A class which can be used to pass to remove to remove something from the middle of the queue.</TD></TR></TABLE> <!-- =========== FIELD SUMMARY =========== --><!-- ======== CONSTRUCTOR SUMMARY ======== --><A NAME="constructor_summary"><!-- --></A><TABLE BORDER="1" CELLPADDING="3" CELLSPACING="0" WIDTH="100%"><TR BGCOLOR="#CCCCFF" CLASS="TableHeadingColor"><TD COLSPAN=2><FONT SIZE="+2"><B>Constructor Summary</B></FONT></TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD><CODE><B><A HREF="../../javatools/util/JQueue.html#JQueue()">JQueue</A></B>()</CODE><BR> Creates a new empty JQueue.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD><CODE><B><A HREF="../../javatools/util/JQueue.html#JQueue(int)">JQueue</A></B>(int size)</CODE><BR> Constructor which takes an initial guesstimate of how many items we expect to store in it</TD></TR></TABLE> <!-- ========== METHOD SUMMARY =========== --><A NAME="method_summary"><!-- --></A><TABLE BORDER="1" CELLPADDING="3" CELLSPACING="0" WIDTH="100%"><TR BGCOLOR="#CCCCFF" CLASS="TableHeadingColor"><TD COLSPAN=2><FONT SIZE="+2"><B>Method Summary</B></FONT></TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> boolean</CODE></FONT></TD><TD><CODE><B><A HREF="../../javatools/util/JQueue.html#empty()">empty</A></B>()</CODE><BR> Is the queue empty?</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> java.lang.Object</CODE></FONT></TD><TD><CODE><B><A HREF="../../javatools/util/JQueue.html#get()">get</A></B>()</CODE><BR> Pull something out of the end of the queue and remove it from the queue.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> java.lang.Object</CODE></FONT></TD><TD><CODE><B><A HREF="../../javatools/util/JQueue.html#peek()">peek</A></B>()</CODE><BR> Get something out of the queue without removing it.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> <A HREF="../../javatools/util/JQueue.QueueKey.html">JQueue.QueueKey</A></CODE></FONT></TD><TD><CODE><B><A HREF="../../javatools/util/JQueue.html#put(java.lang.Object)">put</A></B>(java.lang.Object o)</CODE><BR> Push something onto the queue</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> java.lang.Object</CODE></FONT></TD><TD><CODE><B><A HREF="../../javatools/util/JQueue.html#remove(javatools.util.JQueue.QueueKey)">remove</A></B>(<A HREF="../../javatools/util/JQueue.QueueKey.html">JQueue.QueueKey</A> key)</CODE><BR> Remove an item from anywhere in the queue.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> int</CODE></FONT></TD><TD><CODE><B><A HREF="../../javatools/util/JQueue.html#size()">size</A></B>()</CODE><BR> Returns the number of elements in the queue</TD></TR></TABLE> <A NAME="methods_inherited_from_class_java.lang.Object"><!-- --></A><TABLE BORDER="1" CELLPADDING="3" CELLSPACING="0" WIDTH="100%"><TR BGCOLOR="#EEEEFF" CLASS="TableSubHeadingColor"><TD><B>Methods inherited from class java.lang.Object</B></TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD><CODE>clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait</CODE></TD></TR></TABLE> <P><!-- ============ FIELD DETAIL =========== --><!-- ========= CONSTRUCTOR DETAIL ======== --><A NAME="constructor_detail"><!-- --></A><TABLE BORDER="1" CELLPADDING="3" CELLSPACING="0" WIDTH="100%"><TR BGCOLOR="#CCCCFF" CLASS="TableHeadingColor"><TD COLSPAN=1><FONT SIZE="+2"><B>Constructor Detail</B></FONT></TD></TR></TABLE><A NAME="JQueue(int)"><!-- --></A><H3>JQueue</H3><PRE>public <B>JQueue</B>(int size)</PRE><DL><DD>Constructor which takes an initial guesstimate of how many items we expect to store in it<P><DT><B>Parameters:</B><DD><CODE>size</CODE> - The size of this queue.</DL><HR><A NAME="JQueue()"><!-- --></A><H3>JQueue</H3><PRE>public <B>JQueue</B>()</PRE><DL><DD>Creates a new empty JQueue.<P></DL><!-- ============ METHOD DETAIL ========== --><A NAME="method_detail"><!-- --></A><TABLE BORDER="1" CELLPADDING="3" CELLSPACING="0" WIDTH="100%"><TR BGCOLOR="#CCCCFF" CLASS="TableHeadingColor"><TD COLSPAN=1><FONT SIZE="+2"><B>Method Detail</B></FONT></TD></TR></TABLE><A NAME="get()"><!-- --></A><H3>get</H3><PRE>public java.lang.Object <B>get</B>()</PRE><DL><DD>Pull something out of the end of the queue and remove it from the queue.<P><DD><DL><DT><B>Returns:</B><DD>The object in the end of the queue.</DL></DD></DL><HR><A NAME="size()"><!-- --></A><H3>size</H3><PRE>public int <B>size</B>()</PRE><DL><DD>Returns the number of elements in the queue<P><DD><DL><DT><B>Returns:</B><DD>The number of elements in the queue.</DL></DD></DL><HR><A NAME="remove(javatools.util.JQueue.QueueKey)"><!-- --></A><H3>remove</H3><PRE>public java.lang.Object <B>remove</B>(<A HREF="../../javatools/util/JQueue.QueueKey.html">JQueue.QueueKey</A> key)</PRE><DL><DD>Remove an item from anywhere in the queue.<P><DD><DL><DT><B>Parameters:</B><DD><CODE>key</CODE> - The key which was returned from put().<DT><B>Returns:</B><DD>The object that was removed.<DT><B>See Also:</B><DD><CODE>Queue#put(Object)</CODE></DL></DD></DL><HR><A NAME="put(java.lang.Object)"><!-- --></A><H3>put</H3><PRE>public <A HREF="../../javatools/util/JQueue.QueueKey.html">JQueue.QueueKey</A> <B>put</B>(java.lang.Object o)</PRE><DL><DD>Push something onto the queue<P><DD><DL><DT><B>Parameters:</B><DD><CODE>o</CODE> - The object to push.<DT><B>Returns:</B><DD>An external key that can be passed to remove() to pull it from the queue. The value of the key should be regarded as meaningless to external parties.<DT><B>See Also:</B><DD><CODE>Queue#remove(QueueKey)</CODE></DL></DD></DL><HR><A NAME="empty()"><!-- --></A><H3>empty</H3><PRE>public boolean <B>empty</B>()</PRE><DL><DD>Is the queue empty?<P><DD><DL><DT><B>Returns:</B><DD><CODE>true</CODE>: the queue is empty; <CODE>false</CODE>: it is not...</DL></DD></DL><HR><A NAME="peek()"><!-- --></A><H3>peek</H3><PRE>public java.lang.Object <B>peek</B>()</PRE><DL><DD>Get something out of the queue without removing it.<P><DD><DL><DT><B>Returns:</B><DD>The object at the end of the queue.</DL></DD></DL><!-- ========= END OF CLASS DATA ========= --><HR><!-- ========== START OF NAVBAR ========== --><A NAME="navbar_bottom"><!-- --></A><TABLE BORDER="0" WIDTH="100%" CELLPADDING="1" CELLSPACING="0"><TR><TD COLSPAN=3 BGCOLOR="#EEEEFF" CLASS="NavBarCell1"><A NAME="navbar_bottom_firstrow"><!-- --></A><TABLE BORDER="0" CELLPADDING="0" CELLSPACING="3"> <TR ALIGN="center" VALIGN="top"> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="../../overview-summary.html"><FONT CLASS="NavBarFont1"><B>Overview</B></FONT></A> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="package-summary.html"><FONT CLASS="NavBarFont1"><B>Package</B></FONT></A> </TD> <TD BGCOLOR="#FFFFFF" CLASS="NavBarCell1Rev"> <FONT CLASS="NavBarFont1Rev"><B>Class</B></FONT> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="package-tree.html"><FONT CLASS="NavBarFont1"><B>Tree</B></FONT></A> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="../../deprecated-list.html"><FONT CLASS="NavBarFont1"><B>Deprecated</B></FONT></A> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="../../index-all.html"><FONT CLASS="NavBarFont1"><B>Index</B></FONT></A> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="../../help-doc.html"><FONT CLASS="NavBarFont1"><B>Help</B></FONT></A> </TD> </TR></TABLE></TD><TD ALIGN="right" VALIGN="top" ROWSPAN=3><EM></EM></TD></TR><TR><TD BGCOLOR="white" CLASS="NavBarCell2"><FONT SIZE="-2"> <A HREF="../../javatools/util/IteratorToEnumeration.html"><B>PREV CLASS</B></A> <A HREF="../../javatools/util/JQueue.QueueKey.html"><B>NEXT CLASS</B></A></FONT></TD><TD BGCOLOR="white" CLASS="NavBarCell2"><FONT SIZE="-2"> <A HREF="../../index.html" TARGET="_top"><B>FRAMES</B></A> <A HREF="JQueue.html" TARGET="_top"><B>NO FRAMES</B></A> <SCRIPT> <!-- if(window==top) { document.writeln('<A HREF="../../allclasses-noframe.html" TARGET=""><B>All Classes</B></A>'); } //--></SCRIPT><NOSCRIPT><A HREF="../../allclasses-noframe.html" TARGET=""><B>All Classes</B></A></NOSCRIPT></FONT></TD></TR><TR><TD VALIGN="top" CLASS="NavBarCell3"><FONT SIZE="-2"> SUMMARY: <A HREF="#nested_class_summary">NESTED</A> | FIELD | <A HREF="#constructor_summary">CONSTR</A> | <A HREF="#method_summary">METHOD</A></FONT></TD><TD VALIGN="top" CLASS="NavBarCell3"><FONT SIZE="-2">DETAIL: FIELD | <A HREF="#constructor_detail">CONSTR</A> | <A HREF="#method_detail">METHOD</A></FONT></TD></TR></TABLE><!-- =========== END OF NAVBAR =========== --><HR></BODY></HTML>⌨️ 快捷键说明
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